Rover 5 Explorer board Question

Community General Discussions
1

Hi, I am currently assembling my Rover 5, I have connected the Motors, encoders and the batteries  (6 x NiMh AA,s).

I plugged in a 12vdc 1amp plug pack, and flipped the power switch to charge, After about 15 - 20 seconds, I noticed a smell and turned the charger off, I went over both sides of the board and all looked fine, I did find however, the Resistor directly behind the power switch, was warm to hot.

      After it cooled down, I reconnected the charger and same again after a sort time it began getting warm then hot ( think the smell was some flux around the resistor.) Is this normal, BTW this only happens when connecting the charger, When I turn on  power ( switch to right ), the red led comes on, Nothing gets warm or hot, which i assume that is normal.

Ok, here are some measurements I have taken.

I Checked the voltage on the charger with no load, It was up around 19 volts, When it is connected to the Explorer Board, it measures around 8 volts, While the board is in Charge mode.

Hope this is enough Info, I dont want to procced further till I sort this out.

Cheers Peter

2

Charging LiFePo4 batteries
OddBot,

Groucho is using a LifePo4 battery (huge, 24v 100 amp-hrs). The only way I can really charge the batteries without lifting 90 lb of battery out of the robot is to charge it in place.

For now, I just plan on turning things off, and unhooking the battery from the load and hooking it up to the charger (yes, a specialty charger for LiFePo4 batteries). Is this safe to do?

Eventually I plan on putting the charge circuitry inside the robot and having Groucho plug himself in with a strict protocol (insert plug which powers a 24v power supply. Move the robots electronics to the power supply. Remove all the load from the battery, start the charger.) I’ve left out too many steps here, but that’s the basic algorithm. There will be tests to make sure that everything is setup properly each time.

And does anybody know of a good source for high power (100 amp 24+ volt DC) relays? Preferably DPDT that can be activated by 5 volts. I can deal with 12 volts if necessary because I need that for some of the servos.